The invention relates to a radial plunger pump, and in particular, to a construction for fixing a pintle to a pump housing.
A radial plunger pump generally comprises a pintle in which a suction and a discharge passage are formed and which is secured to a pump housing, while a rotor having a plurality of radially extending cylinder bores formed therein is rotatably fitted around the pintle, with a plunger being slidably disposed in each of the cylinder bores. A guide ring is disposed within the pump housing in eccentric relationship with the center of rotation of the rotor so that the rotation of the rotor within the guide ring causes a reciprocating motion of the plungers to thereby increase or decrease the volume of a pump chamber defined inside the respective plunger to provide a suction and discharge of a working oil.
In a conventional radial plunger pump, the pintle is secured to a lateral side of the pump housing from the outside, with its inner end being inserted through an opening formed in the lateral side of the housing so that the rotor may fit around the inserted portion of the pintle (see Japanese Laid-Open Patent Application No. 1,876/1986).
In such a conventional construction for fixing the pintle, the pintle which is secured to the outside of the pump housing must be assembled in the opposite direction from the rotor and the guide ring which are received within the pump housing, thus presenting an inefficiency in the assembling operation. This also involved the likelihood that the pintle may be assembled in a wrong position, whereby the suction groove and the discharge groove formed in the pintle may be located in interchanged manner, preventing a pumping action. Such a wrong assembly could be detected only upon inspection which takes place after the completion of the assembly. In addition, since the pintle is secured to the external surface of the pump housing with a seal member interposed therebetween, an oil leakage is likely to occur, thus presenting a problem of reliability.